The field of the present invention is fat spreads and the manufacture of fat spreads.
Two fat spreads comprise the bulk of the consumer market in these goods. Butter and margarine. Butter is subject to a federal standard requiring a minimum of 80% fat. In today's health conscious environment, it has become generally understood that a diet reduced in fat content is beneficial. The level of fat in butter has been a continuing drawback to its use.
Margarine has made substantial inroads into the butter market. Margarine is a water and oil emulsion, taking its character from the continuous oil phase. The presence of oil rather than butter fat has made this spread appealing to many consumers. Further, the selection of vegetable oil may also be made to eliminate cholesterol content and the like.
In margarine, the aqueous phase is a blend of water, salt (optional), whey (optional) and various other ingredients such as buttermilk and milk powder to enhance the flavor. The aqueous phase may contain various preservatives such as sodium benzoate, potassium sorbate, citric acid or EDTA. The oil phase is a blend of liquid vegetable oil (typically soybean), partially hydrogenated vegetable oil (typically soybean), lecithin (optional), mono and diglycerides (optional), beta carotene, vitamin A and natural or artificial flavor. Margarine is manufactured by combining the aqueous phase ingredients in a mix tank which is then pasteurized. The oil phase ingredients are combined in a tank, heated and agitated. The oil phase and aqueous phase are then separately pumped to a calibrated metering system. The oil and aqueous phases are here blended proportionally to create a water and oil emulsion. The emulsion is pumped from a holding tank to a scraped surface heat exchanger which quickly chills and crystallizes the emulsion.
The scraped surface heat exchanger system can be basically described as a two-part system. In the first part, the emulsion enters the chiller tube at a temperature of 90.degree. F. As it passes through the chrome plated tubes, it is cooled. The dwell time is approximately 1 to 2 minutes. At this point, the emulsion temperature has been decreased to 45.degree. to 50.degree. F. The chrome plated tubes combine a heat exchanger with a mixing mechanism. The heat of the emulsion is removed as it is agitated and propelled into contact with the cold surface of the tubes. In the second part of the system, the emulsion is pumped into a container where the emulsion is tempered by brief and intermittent agitation. During this phase, the chilled fat crystals begin to form a crystallized matrix. During crystallization, the particles of oil become extremely small and they entrap the tiny droplets of water liquid. The margarine is then packed into tubs or cubes at about 45.degree. F.